Man who was not always trying to fortell the future,but was instead making political commentary disguised as soothsaying (most political commentary would have been illegal in his time)Because human beings keep repeating themselves many quatrains will incedently come true,and they will keep comming true until humans actually change for legit.Also the fact that people who influence history often have read nostradamus helps.

Nostradamus predicted WW1/2
The human race was destined to have a war of simaler magnitude at sometime,and Hitler had read Nostradamus and used the word hister to catipult himself into power so who knows if the word hister isnt used in the quatrain mabey WW2 would have been lead by some other psyco.

A charlitan who possesses no greater "clairvoyance" than Miss Cleo. Employing techniques of vague predictions commonly employed by psychic hotlines today, Nostradamus' 'prophecies' could have been interpreted as anything.